William kurtz



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WITNESSE UNITED STATES PATENT GEFIcE.

WILLIAM KURTZ, OF NEV'YORK, N. Y.

PHOTOMECHANI'CAL PRINTING.

SPEGIFICATION forming part of Letters Patent No. 498,396, dated May 30,1893.

Applioationiiled February 23,l 1893. Serial No. 463,328. (No model.) l

city, county, and State of'NeW York, have invented a new and usefulImprovement in Photographic-Printng Methods, of which the following is afull, true, and exact specification,

reference being had to the accompanying drawings.

In printing chromos or colored prints on the lithographie, type,Lichtdruck, gelatine, photogravure, or any other press, either fromhalt-tone plates or from transfers on stone, which have been produced bythe half-tone photoengraving process-or by similar methods, the printsshow in spite of the most perfect register, a so-called moir-effect, adefect which may appear only in a few portions of the picture or recurregularly all over the picture in the form of apattern'resemblingwatered silk, thus rendering it entirely Worthless.This moire-effect or confusion of lines is due to the fact that thecolors are printed one over the other While they should really bearranged side-Wise of each other on the paper,

or cross each other in such a Way as to make confusion or moireimpossible. To avoid this serions defect, instead of making a halftonenegative of the yellow color, another of the red color and half-tonenegatives for every other color that is to be used, all of whichnegatives would be produced by the screen or net in crossed lines, dotsor stippled lines, my negatives are made in single lines by interposingin lieu of the screen or net, a glassplate ruled with parallel linesrunning in one direction only, so that the negatives show only one halfof the picture or color to be reproduced, instead of the more fullyVmodeled negatives in use heretofore.

My invention consists therefore in a process of photomechanicalprinting, in Which half-tone negatives are produced by exposing eachplate with a screen With parallel lines running in one direction only,the lines of one negative running in a different direction from thelines of the other negatives, and then printing in colors from thesehalf-tone negatives, so thatthe lines of the different plates willintersect each other in different directions.

In the accompanying drawings my improved plate is subjected to a singleexposure through a screen, the parallel lines of which run in adifferent direction to the lines of the Iirst screen. rIhe remainingplates are likewise exposed in the same mannerthrough screens, theparallel lines Vof which run in directions differing from the first twoscreens. When a picture is to be printed, forinstance, in three colors,the color-plates are made from the halftone negatives which are obtainedby single exposures by the interpositions of the screens,

shown in Figs. 1, 2 and 3, so that a picture representing one color isobtained in which the stripes run in one direction, say horizontally, asshown in Fig. 4, while the pictures obtained by the remainingcolor-plates are produced in stripes that run diagonally to the lines ofthe first plate and in opposite directions to each other, as shown inFigs.5 and 6.

The printing-plates are produced from the vhalf-tone negatives by thephoto-etching process in the well-known manner, so that when the colorsare printed onev over the other in colored printing inks,la picture isobtained, in which the light and shade ofthe original are fully shown,although each color has been photographed' for only one half of itsarea, the remaining half being taken up by the lines. The moire patternor similar defects are thereby entirely obviated, as the color-stripesintersect each other and reproduce thereby theoriginal picture in a morecomplete and artistic manner. One of the colors may be printed from agrained plate and the picture then be completed by printing the othercolors over the color produced by the grained plate from printingplates, the lines of which cross each other at right angles. When thepicture is to be printed in four colors, a fourth printing-plate isused, the lines of which inlines run in diierent directions to eachother, next producing printing plates from said halftone negatives andnally printing in different colors from these printing-plates, so thatthe lines of the different printing-plates will intersect each other indierent directions, substantially as set forth.

In testimony whereof I have signed my n naine to this specification inthe presence of two subscribing witnesses.

WILLIAM KURTZ. N Vtnesses;

OWEN WARD, CLARENCE R. COMES.

